Various materials, such as sewer pipes, water pipes, utility conduit, etc. are required to be installed and often serviced below ground. Invariably, some of these pipe sections may need to be cut to size before joining abutting ends or have various sections replaced as they degrade. This may require plunge cuts or cross cuts of pipe having diameters ranging between, for example, one inch to twelve inches or more. Such pipes may comprise a variety of materials including metal, steel, copper, ductile iron, concrete and plastic, such as polyvinyl chloride (PVC).
Generally, excavation is needed to service or replace existing underground pipe. For pipes larger than six inches in diameter, access from multiple sides of the pipe may be necessary given the limitations of existing tools. For example, typical abrasive cutting wheels are limited to cutting depths no greater than the radius of their cutting disk. Consequently, they may require the cutting wheel to completely traverse the periphery or circumference of the pipe. This may require excessive hand excavation which is time consuming, labor intensive, and expensive. Additionally, in many instances a portion of underground pipes may lie in locations where excessive excavation may result in damage to property or made difficult by various obstructions such as the presence of utility services, concrete foundations, large boulders, and/or bedrock.
Once the excavation is finished, assuming excavation on all sides of the pipe was possible, typical cutting tools such as abrasive cutting wheels may be forced into awkward cutting positions to facilitate a cut. These positions may have an impact on the ability to align the starting and stopping points of the cut as the cutting wheel traverses the pipe. Further, the use of current cutting tools, such as cutting wheels and saw chains, may be difficult in certain situations, as their cutting elements may also contribute to their ineffectiveness.
Finally, in addition to cutting pipes of various materials, it is often needed, for example during fire and rescue operations, to cut through various objects such as roofs, doors, walls, etc. Currently available abrasive cutting chains such as those used for cutting concrete are not practical for cutting materials, such as utility pipe, composition roofs, metal fire doors, etc., due in part to the large block design of the cutting elements. These chains can also experience snagging and breakage due to the acute angles they generate as they cut through the objects. Additionally, the cutting elements used in concrete cutting chain are typically designed with multiple layers of diamonds in a support matrix. It is necessary to erode the support matrix to expose additional diamonds to the cutting surface. Using concrete cutting chain to cut various materials other than concrete is not effective because the support matrix may not be eroded during the cut thereby failing to expose the abrasive to the material. Finally, typical wood chains are not suited to cut these materials due to the fact that their cutting edges are typically made of a hardened steel, which will dull, wear and/or break when used with materials other than wood.